The disposal of ever-increasing quantities of waste materials is a significant challenge in many parts of the world and is becoming a more significant problem as the world's population becomes increasingly urbanised. Furthermore, the increasing human population and increasing levels of affluence are resulting in larger quantities of waste materials of various kinds being generated. Disposal strategies currently utilised for dealing with wastes include landfill, biological degradation by various means, combustion, and various chemical treatment processes. However, each of these methods suffers from one or more disadvantages. For example, existing disposal methods may cause pollution, may be energy intensive, or may be wasteful of limited resources such as land. Additionally, many waste materials constitute a source of useful energy if efficient means of recovery of that energy can be devised. For example, waste incineration is an effective way of decreasing the bulk of waste material for disposal, but typically the heat generated by the incineration is not recovered, and in addition the process can lead to the generation of pollutants such as nitrogen oxides and dioxins, and the generation of large quantities of greenhouse gases. Hence there is a need for improved waste treatment or disposal processes which are environmentally benign and which result in the recovery of useful energy from the wastes.
It is an object of the present invention to provide an efficient method for the recovery of useful energy from carbon-containing materials, and simultaneously to provide an environmentally acceptable way of disposing of waste materials with minimal adverse environmental impact.